Nature of Time Dilation and Length Contraction

Physics Monkey,

Before the universe existed, there was no time, agreed? Time is intrinsically linked to mass, and without mass, or anything to measure for that matter, there is no time. Without substance, time is nonexistent, right? So we need to consider the relationship between mass and time. Mass exists in our universe in varying locations with relative positions. Matter, as we all know, interacts with other matter in many complex ways and energy is converted from one form into another. If we consider the universe to be constructed from discrete nodes whereby this fabric of nodes allows transfer of energy between adjacent nodes, then why shouldn’t the reactions between nodes be transferred from one point to another based on a constant (God, this is hard to explain!) physical, communication process.

If these nodes were created by the presence of mass then we maybe could assume a relationship between nodes (yes, aether) and mass. The nodes, being compressible, would be affected by mass and their density affected, hence, the “apparent” time in which events take place would be affected and “time” would be measured to dilate, when in actual fact, it’s the physical processes between nodes which has been altered.

 

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I do like the equations; using equations keeps you from making logical mistakes. If you can show that time can be eliminated from the equations then you will demonstrate that your idea is at least logically sound. Obviously it takes more than just logic for a theory's success, but logic is certainly a necessary condition for any successful theory.

And how can you have "cause and effect" without time? The cause always comes before the effect, and before denotes an ordering in time. How can you have a "process" without time?

My problem with accepting it is that it seems like nonsense to me, you have yet to make any convincing argument for your idea. First, every single description you have made about why something doesn't require time has been loaded with time-based words and concepts. All you have shown so far is that English has a lot of synonyms for the word "time". Second, you have not shown mathematically how we can get equivalent predictions of physics results without using the concept of time. Third, even if you were to do the first and second you haven't shown why I would want to abandon such a useful and simple concept. What situations does your "timeless" idea clarify, or where does the use of the idea of time lead to an observable mistake?

-Dale

 

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I didn't feel insulted here and, having dealt with dav before, I don't think that an insult was intended. My skin is not that thin, but thanks for the thought!

-Dale

 

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Hi dav,

This is precisely the sort of thing I can't agree with, dav. What does "before the universe existed" mean? It seems to me that you just can't have before without time. As someone who has thought a good deal about this very thing, I appreciate how seriously difficult it is to not use the concept of time, but it has to be done.

Also, about the insults comment, I was referring to the comments you made about not thinking deeply and so forth. I wasn't offended (I don't think you were even talking to me), and clearly neither was Dale. I just try to campaign for some civility around here from time to time because I think it makes these discussions more pleasant. Of course, I personally regularly fail at said goal of civility.

 

Wouldn't light-time, l = ct, qualify as removing time from the equations?

 

If I were trying to get rid of time that is probably the approach I would take. You might be able to get somewhere using Geometric Units. I am not convinced that simply changing time from units of seconds to units of meters would actually get rid of time. I tend to think that it would instead simply put it on an equal level with the spatial dimensions. But I definitely think it is the most promising starting-point if getting rid of time is your goal.

-Dale

 

It's not my goal, it's Dav's. But, I was just thinking... I believe it could be used to create "cycle-meters", which would be sort of a change-change unit that Dav may be searching for.

edit: Which while still a temporal unit, would be one based entirely on measured change and without the intermediate concept of time.

 

Quote from Wikipedia..."In geometric units, every time interval is interpreted as the distance travelled by light during that given time interval. That is, one second is interpreted as one light second, so time has the geometric units of length. This is dimensionally consistent with the notion that, according to the kinematical laws of special relativity, time and distance are on an equal footing."

This is EXACTLY what I'm trying to get at! That somehow, the universe unfolds through a set of processes determined by nothing more than an "order" of unfolding events based on information and physical processes causing other adjacent nodes to be affected. The distance between nodes (or the relative compression of nodes) affects the way events unfold.

Also, I thought that time didn't exist before the universe began. So how did the universe begin if time was required. Obviously, the universe began before time, not the other way round. This further supports my argument, doesn't it?

 

"Order" means that events follow one after another in time. How can you have a process, or "ordering" of events without time?

The concept of an underlying time 'parameter' follows from an elementary observation that is usually taken for granted: If some process, A, is seen to be synchronized with some other process, B, and B is synchronized with a third process, C, then A is also observed to be synchronized with C.

You sound like you're building an entire philosophy around time not being 'necessary' (whatever that means). Why? The concept of time accomplishes everything you say about events being 'ordered,' and more. It turns a qualitative description of nature into a quantitative one. As Dale pointed out, you won't invalidate time by rewriting the laws of physics and replacing every occurence of the word 'time' with some less precise synonym.

 

Does length exist? Explain how length is part of the universe, apart from being there to provide a method of comparison of the position of one entity to another. Length is nothing more than a way of comparing. Length isn’t real and neither is time.

Based on your argument you could insist that all of our universal mass has no size or relative position without length. In the case of length, the mass came first without the requirement of length. Then length can be used as a tool for comparison. Time is no different.

For your argument to be valid we must assume time to come into existence BEFORE the universe unfolded any events – and this is clearly nonsense.

The reason I hold this view is because we must begin to realise that our universe is purely physical in nature and the notion of time dilation is wrong. It’s not time which dilates but rather the physical properties of our universe i.e. mass. And why does mass oscillate differently depending on its position and speed relative to a gravitational field? Because the “physical” field directly affects the way mass behaves.

The idea is similar to space-time but eliminates the need for time.

 

I suppose you can think up an example of two points with no "length" between them? Don't tell me you think positions are absolute.

So the universe isn't real? Remove length and time and that's what you get: no universe.

How do you define "real" anyway? Unless you do, this discussion is pointless. The only thing I'm inclined to call "real" is the information my senses receive. The notions of space, time, and matter are just parts of an abstract model I use to help structure and make sense of the incoming data my brain has processed.

Again, you're replacing a term in physics with synonyms. This time you're replacing 'length' with 'size.'

Or you could dismiss talk of what happened 'before' time began as nonsensical. See PM's previous post.

Great. Define 'physical.'

The point is that processes in relative motion slow down with respect to an equivalent process at rest. DaleSpam has already posted some good explanations as to why you might as well consider this time dilation.

What "physical field" would this be? Sounds like another aether theory.

You haven't eliminated the need for anything - just shown how the laws of physics can be rephrased in a way that doesn't change their meaning.

 

The length is a relationship between two entities. It's not the length that exists, it is the entities.

Rubbish.

well, time and length are not physical but mass is.

Perhaps. What's wrong with that? It's not like it's at all similar to the aether theories which the MM experiment kicked out.

Why can't the universe be purely physical?

What is DARK ENERGY? What is DARK MATTER? Can science answer this?

Would a physical aether help explain? Why not?

 

Now define "exist." Give me some criteria by which I can assess whether or not something "exists" (by your definition). Note that giving a few examples does not qualify as a definition.

Once you've come up with a good definition, explain why physicists should care about it, ie what makes it useful as opposed to a redundant label you assign. So far all you're doing is playing around with terminology, which is metaphysics at best. Its why I usually stay out of this kind of discussion: they go round in circles and are ultimately pointless. You can say that time and distance do or do not 'exist', or are or aren't 'necessary' based on your conception of 'existence' and 'necessity', but it won't change anything since it is outside of the scope of science.

What is "mass" or "matter" ? Can you answer this?

 

It appears that some of you are having a hard time at grasping what dav57 is implying. He is claiming that time is not a factor in physical interactions. For example, if you have two charged spheres seperated by a distance, the only factors in determining the force between them, and the acceleration caused by the force, is the amount of charge they carry and the distance between them. The interaction doesn't know, or care, what time is. To explain the resulting acceleration, time is needed, but time is only an abstract idea and not a factor influencing the interaction.

Of course, this is how it used to be until Relativity came along. In Relativity, time has now become a physical factor influencing all interactions instead of just an abstract idea. So now, the interaction of the two charged spheres I described above is not only influenced by the amount of charge they carry and the distance between them, but local time, and even supposedly the speed of observer's observing the interaction. In other words, Einstein took an abstract idea and tried to made it into a physical factor just so that he can satisfy his assumption. This is one of the many reasons I don't support relativity. I, like dav57, still believe that time is just the measurement of distance between two events, and not a factor actually influencing those events.

 

dav57,

I think I know why reactions slow down in objects that are moving through gravitational fields, and the explanation is so simple it's pathetic.

First, let's assume that the speed of light is only equal to c relative to the gravitational field that it is travelling through. If this is the case, then the speed of light in an object that is moving through a field will change, and the amount of change will depend on the direction the light is travelling in the object. So for example, if the light in the object is moving in the same direction as the object is moving in the gravitational field, the light would slow down relative to the object. However, if the light in the object is moving in the opposite direction of the object's motion through the gravitational field, then the speed of the light would increase relative to the object. But the interesting thing is that if you take the speed of of light travelling in that object in all six directions (for all three dimensions) and add them together and divide them by six to get the average speed of light, you'll find that the average speed of light in an object that is moving through a gravitational field is always less then c. And the faster the object moves through the gravitational field, the lower the average speed of light is in that object. So, you may ask, how does the decreased speed of light in that object influence the speed of reactions in that object? Here are three ways it does:

1) First let's assume that the electrostatic interaction is the result of an exchange of light-speed particles (virtual photons). If the average speed of light decreases, then the speed of those light-speed particles would decrease as well. Because of their decreased speed, they have less energy, so less energy is transferred in the interaction. If less energy is transferred, then the electrostatic field is weaker, which in turn results in a weaker force generated by that field. The weaker force results in the slower acceleration of charged objects, causing the whole electrostatic interaction to slow down. So all interactions that are the result of the electrostatic force, including all chemical reactions, would slow down for an object moving through a gravitational field.

2) Second, if the average speed of light decreases for an object that is moving through a gravitational field, then the average speed of electric fields in electric conductors in that object would slow down as well. The slower electric fields in those conductors would cause the electrons to move slower. This means that all electronics would slow down, and the frequency of all oscillating electric circuits would decrease, in an object that is moving through a gravitational field. (By the way, atomic clocks have electric circuits).

3) Although the true mechanism behind particle decay is still unknown, I once read someone suggest that you can look at an unstable particle as having light-speed particles, or waves, bouncing in the inside, and when certain conditions were met, the unstable particle would decay. If this is true, then the decreased speed of light in an unstable particle that is moving through a gravitational field would cause the decreased speed of the light-speed particles, or waves, that are bouncing around in that particle. This decreased speed would mean that the condition for decay would take longer to be met, which would result in a longer half-life of that particle. This can explain why particles that are travelling at high speeds in particle accelerators, and muons that are travelling at high speeds through our atmosphere, take longer to decay then the ones that are stationairy in a gravitational field. (By the way, no one has to tell me that #3 is a stretch. I know that. I simply can't can't explain how the decreased average speed of light would influence particle decay when I don't know the mechanism behind particle decay).

 

This doesn't make any sense. What does it mean for an absolute property in some physical equation to be superfluous?

They don't. There are invariants in relativity, such as the speed of light. And if you take any two tensors of the same rank and contract them, you get another invariant.

This doesn't make any sense either. First, physicists don't change any properties of space and time. Physicists deduce those properties. And second, the concept of time is not new. It was in Newton's mechanics and in Galileo's relativity before Einstein was ever born.

The rest of your post is so off base that I'm not inclined to respond to it. It is simply not the case that everything is relative in SR, nor is it the case that it was introduced because people thought it was "cool". That's just dumb, and it shows a complete ignorance of the history of the subject.

 

It is very interesting that a self proclaimed Relativy faithful believer and expert has revealed to us that said expert does not understand the working mechanics of the development of the Lorentz contraction in a contracting body, when the relativistic contraction must be considered one of the very most important bedrocks of relativity theory.

Racing car drivers are very glad when they drive beyond their ability and spin out into an energy absorbing safety barrier, so that they get a little banged up but do not crash and burn.

Likewise, a writer may be very glad that they can create their own safety barrier by proclaiming that a cogent argument confronting them is too bad to respond to.

 

If this is exactly what you are trying to get at then I am glad I could help. However, if this is what you intended then I don't think that our positions are really that different. In geometric units time exists, it just has dimensions of length. As you say, in geometric units the distance between objects or events affects the way that events unfold, whether that distance is most easily measured with a clock or a rod. I have no problem with that position. Also, in geometric units all orderings of events are spatial orderings, that doesn't mean that events can't be ordered from "first" to "last" just that there is no real difference between that and ordering them from "top" to "bottom". I have no problem with that position either. If you want to say that time is just another distance then I won't argue, but if you want to say that it does not exist then I think you still have a ways to go and the geometric units is just a starting point.

Personally I don't think that the phrase "before time" makes any sense at all, so it is hard to see how it further supports any argument at all. Also, I don't think that anything is obvious about the beginning of the universe.

-Dale

 

What?

When I see a cogent argument, I'll respond to it. In fact sometimes I even respond to arguments that aren't cogent, like your little "paradox" in that other thread.

 

In the human mind, how can we possibly make any sense out of "before time"?

In my humble ( what? ) opinion, my human mind can only make sense of a sequence of events, which I can only call "time". If someone says "before time" and they are not trying to play a joke on me, then I must presume that they are trying to explain a prior event to what we might most often refer to as time. But, the prior event can only be known as an event. Therefore, it must also be one of the events in a sequence of events which my human mind recognizes as "time".

I am not the least reticent to claim to believe in God. I am also not reticent to claim that any credence of the reality of "before time" can only be understood by the same God who apparently has operated out of human time and has apparently created human time and human perception of time.

There are a vast number of things that our human minds can study and understand in scientific approaches. But after a certain point, we go beyond science and into religion.

I believe that the study of time is extremely interesting and worthy of scientific study. Science can only go so far.